In the construction of sauna rock heaters of the type which generate combustion gases by the burning of wood, natural gas and the like, it is the general practice to support a pile of rocks in a pan-like structure of heat conductive material to present a relatively large heat-transfer surface area to the rocks yet to properly support the rocks. However, when such a structure is used, water, when poured on the heated rocks, oftentimes accumulates in the bottom of the structure and this tends to cause thermal shock in the same which, over extended periods of time, will eventually cause rupture of the pan-like structure, thereby allowing water to fall onto the source of the combustion gases therebelow. When this occurs, the structure must be removed or otherwise repaired before the rock heater can properly be used thereafter. Thus, to avoid the structural damage mentioned above, a need has arisen for an improved rock heater which prevents the accumulation of water in the pan-like structure described with respect to conventional gas-operated or wood-burning rock heaters.